There is a need for a highly sensitive (> 90%) and specific (> 90%) long term biomarker to both detect and monitor individuals who are heavy users of alcohol. Monitoring short term (3-5 days) alcohol use and abuse by impaired professionals by using urine ethyl glucuronide (EtG) has been shown to be both sensitive and specific (> 90%). Recently, evidence has emerged that EtG in hair may be able to detect long term abusers of alcohol with a sensitivity approaching 100%. With these results as background, this Phase I study will extract EtG from hair of patients admitted for residential treatment of alcohol use disorders at Rogers Memorial Hospital (RMH). The demographics of RMH's alcohol treatment program include impaired professionals and more than 40% of patients are women. The aim of this Phase I study is to determine whether EtG levels in hair can distinguish between heavy abusers of alcohol (n= 50) and non-drinking (n=50) with a sensitivity and specificity of greater than 90%. Using the statistical procedure of a receiver-operating characteristic (ROC) plot we will examine the whole spectrum of sensitivities and specificities over the entire range of hair EtG values obtained. We will also investigate the effects of long- term abstinence of the alcoholic patients on their hair EtG levels by analyzing hair samples taken from them after 45 days of residential treatment. In this study, feasibility of hair EtG as an alcohol long term abuse marker is defined as a test having a sensitivity and specificity of 90% or greater. If feasibility in this Phase I study is established, a Phase II study will expand to include women and pregnancy, binge and college drinking, transplant recipients and the development of a commercial hair EtG test. Alcohol abuse is an illness that has monumental consequences on people's every day lives, their physical and mental health, and the economies of nations. Treatment of an illness is dependent upon an early diagnosis and the current methods of self-reporting and the diagnostic tests for alcohol that are available do not detect most instances of alcohol abuse. The hair ethyl glucuronide test may prove to have superior sensitivity, specificity and ability to detect chronic alcohol abuse than the alcohol biomarkers currently in use, and be the first of a new generation of alcohol biomarkers that have a really significant impact on the treatment of this disease. [unreadable] [unreadable] [unreadable]